Automatic reclosing circuit breakers



Oct. 30, 1956 w. EDWARDS 2,769,054

AUTOMATIC REC/LOSING cmcun BREAKERS Filed April 21, 1951 WIITNESSES:

INVENTOR Ar1drew W. Edwards.

United States Patent AUTOMATIC RECLOSIN G CIRCUIT BREAKERS Andrew W. Edwards, East McKecsport, Pa., assignor to Westinghouse Electric Corporation, East Pittsburgh, Pa, a corporation of Pennsylvania Application April 21, 1951, Serial No. 222,284

Claims. (Cl. 200-89) My invention relates generally to circuit interrupters, and it has reference in particular to automatic reclosing circuit breakers of the dashpot delayed type.

One object of my invention is to provide in an automatic reclosing circuit breaker for insuring accurate stepping of an operation counting integrator.

Another object of my invention is to provide in an automatic reclosing circuit breaker for utilizing fluid pressure operated means for stepping a counting device each time the breaker operates, and for accurately determining stepping of the counting device in response to each operation.

Yet another object of my invention is to provide in an automatic reclosing circuit breaker for supplying a surplus of fluid to a counting device for causing it to step in response to circuit opening operations of the breaker, an actuating a stop to determine accurately the stepping of the counting device.

it is also an object of my invention to provide in an automatic reclosing circuit breaker having a fluid dashpot time delay device for supplying suflicient fluid from the dashpot device for stepping the piston of an operation counting mechanism further than is required, and for restraining movement of the piston past the desired point by means responsive to operation of the circuit breaker.

These and other objects of this invention will become more apparent upon consideration of the following detailed description of a preferred embodiment thereof, when taken in connection with the attached drawing, in which the single figure illustrates a substantially central vertical section view of a circuit breaker embodying this invention.

The invention is illustrated on the drawing as being embodied in one form of automatic reclosing circuit breaker, with the particular breaker herein illustrated being more particularly described and claimed in the copending applications of I. M. Wallace ct al., Serial No. 719,524, filed December 31,1946, on Circuit Interrupters; l. M. Wallace et 211., Serial No. 719,572, filed December 21, 1946, on Circuit Interrupters; I. M. Wallace et 211., Serial No. 718,942, filed December 28, 1946, on Circuit lnterrupters; and I. M. Wallace et al., Serial No. 8,044, filed February 13, 1948, on Circuit Interrupters, all of which are assigned to the same assignee as this invention. This circuit breaker is mounted in a metal tank 2 having a closed bottom wall and an open top, and adapted to be filled with a liquid up to the level L, preferably an arc extinguishing liquid such as oil or the like. Preferably, the tank is lined at least over the bottom wall and up to a point adjacent the open top of the container with a liner 3 of insulating material such as fiber, or the like. The upper end of tank 2 is provided with an outwardly extending flange 4 on which the flange 3 of a cover casting 6 is adapted to'be seated, preferably with a gasket 10 interposed therebetween. Flange 8 of cover casting 6 may be provided with an integral lip 12, and the cover may be secured to the tank in any desired manner, such for example, as by bolts (not shown) extending through H openings in cover flange 8 and secured to suitably formed brackets on the tank.

The breaker contacts, are extinguishing structure, and the contact actuating mechanism are all adapted to be supported tank 2 from cover casting 6 by means of a plurality of integral supporting lugs 16 (only one of which is shown) depending from the top wall of the cover casting and adapted to engage spacers 18 of insulating material suitably secured to supporting lugs 16 and to a supporting casting 29. A supporting plate 22 may be supported from casting 20, so that a solenoid coil 24 may be mounted between casting 20 and supporting plate 22, with the central opening in the coil aligned with openings provided in casting 20 and plate 22. Supporting casting 2% and supporting plate 22, together with the bolts (not shown) securing them together, are of a magnetic material, such as iron or the like, to complete a magnetic circuit of low reluctance outside of solenoid coil 24, which terminates at opposite ends of the central opening through the coil in which the working air gap of the coil is located.

Spaced stationary contacts 26 of the breaker are supported within an insulating tube 28 at the lower end thereof, and on opposite sides of the tube, respectively. Tube 28 which may be of any desired insulating material, such as fiber or the like, is supported at its upper end from plate 22 by supporting brackets 30 which are welded or otherwise secured to plate 22, and have screws for securing tube 28 thereto, with the upper end of tube 28 being closely adjacent to, but spaced from plate 22. Stationary contacts 26 are each mounted on its own supporting bracket 32, with each bracket having a U-shaped portion for receiving the lower edge of the tube 28 and being secured thereto as by a bolt 34. Tube 28 has opposed vent openings 35 in opposite sides, located directly above stationary contacts 26, respectively.

A movable bridging contact 36 for engaging the contacts 26 is mounted on an insulating contact actuating rod 44 by a pivot 38. The upper end of contact actuating rod 44 has connecting links 46 pivoted thereon as by a pivot pin 48, with the upper ends or" these connecting links mounted on a common pivot pin 56 for a pair of toggle levers 52 and 54. Toggle levers 52 and 54 are both formed of sheet material, with lever 54- being bent to substantially channel form with outwardly extending flanges 56 adapted to be received at the free ends thereof in recesses 58 provided in the spaced downwardly depending fingers of an angled supporting bracket 68, which in turn is secured as by a screw 64 to a lug 62 integral with the cover casting. A coil tension spring 63 has one end hooked into an opening provided in toggle lever 52, and has the opposite end thereof hooked over an integral spring support on the cover casting. Toggle lever has an integral hook portion 55 passing through an opening in lever 54 to limit separation of the levers.

It will be observed that in the closed circuit posit" the breaker illustrated on the drawing, the l ne of ac ion or" toggle spring 63 is below the pivot suppo g recesses 58 for toggle lever 54, and accordin ly, the toggle spring acts to bias bridging contact 36 into engageme with stationary contacts 26 of the breaker, under a predetermined pressure. However, as soon as contact oper ting rod 4 3 moves upwardly to separate the bridging act from the fixed contacts of the breaker, toggle lever 5 will pivot about recesses 53 and the line of action of toggle spring 63 will thus be caused to approach pivot rece that in response to a very small contact separation the line of action of toggle spring will pass through pivot recesses 58, which is the on-center position of the resilient toggle arrangement comprising toggle levers 52 and 54 and toggle spring 63. As a practical matter, the opening movement of the contacts necessary to move toggle lever 52 and 54 to the on-center position mentioned above may be made very small, in one actual device being on the order of one-quarter of an inch. When toggle levers 52 and 54 reach their on-center position referred to above, further relative movement of the two toggle levers in the same direction is prevented because the upper edge of toggle lever 52 engages the base of the central channel formation of toggle lever 54. Moreover, since the point at which toggle spring 68 is hooked into lever 52 then substantially coincides with recesses 58 in which toggle lever 54 pivots during contact opening movement, it will be apparent that the remainder and major part of contact opening movement will occur substantially uninfluenced by toggle spring 68.

Substantially the reverse of the above operation occurs when contact operating rod 44 moves downwardly to close the circuit from the full open contact position, because during the first and major part of contact closing movement, levers 52 and 54 will be in engagement so that such movement will be uninfluenced by toggle spring 63. However, as soon as pivot 59 passes below a line drawn from the remote end of toggle spring 68 through pivot recesses 58 for lever '4, toggle spring 63 will then be effective to move the toggle levers toward the position shown, and the force exerted by toggle spring 68 thus tending to close the contacts will continue to increase as toggle levers 52 and 54 move further away from their on-center positions.

Solenoid coil 24 previously mentioned, is adapted to be energized under certain conditions for automatically opening the circuit breaker contacts. The central opening through coil 24 preferably is provided with a cylinder sleeve 74 in which a solenoid core 76 is adapted to be slidably mounted in a piston-like manner. The sleeve 74 connects with an annular passage 77 which opens in turn into a passage 78 for venting the sleeve.

A contact actuating sleeve 82 is telescoped over contact actuating rod 44, and its lower end is received in core 76, preferably being threadably mounted therein. A coil compression spring 86 is provided within actuating sleeve 82 on contact actuating rod 44, and it is adapted to react between core 76 and a collar secured to actuating rod 44 by a pin 88 extending transversely through actuating rod 44.

The circuit through the circuit breaker thus far described may now be traced from the point where it enters tank 2 through one of a pair of terminal bushings 90 (only one being shown), with each bushing being secured to cover casting 6 as by bolts 94, and each being provided with a conductor element which extends through the bushing and emerges from a reduced extension 96 of the bushing nested in an opening provided in the top wall of cover casting 6. The circuit proceeds by conductor 98 directly to one fixed contact 26 of the breaker. When the contacts are in engagement, the circuit then proceeds through bridging contact 36 to the other fixed contact 26, and then by way of a conductor 1% to one terminal of solenoid coil 24. The other terminal of coil 24 is adapted to be connected by a conductor 102 to the conducting means in the other terminal bushing 90. It will be apparent that solenoid coil 24 is connected in series in the circuit through the circuit breaker so as to be energized at all times an amount dependent upon the value of the load current flowing in the circuit.

i For any given rating of circuit breaker, solenoid coil 24 is designed to become sufficiently energized when the load current in the circuit exceeds its rating as to attract core 76 and move it upwardly within sleeve 74. Assuming the upper end of sleeve 74 to be closed so fluid cannot escape, core 76 will move upwardly, retarded by the necessity for displacing the liquid in sleeve 74 above the core through the relatively small clearance between the core and sleeves 74 and 82. Accordingly, opening movement of the core will be slowed up by the aforesaid dashpot action an amount determined by the current value of the overload, and, therefore, .an inverse time-current.

characteristic on opening is obtained. As core 76 commences its upward travel, bridging contact 36 being held engaged by toggle spring 68 does not move, so that spring 86 is compressed until the upward force of the spring 86 is sufficient to overcome the force exerted by toggle spring 68, at which time contact actuating rod 44 will start to move upwardly. As soon as actuating rod 44 moves upwardly, the force exerted by toggle spring 68 begins to decrease and in a very short distance has substantially no value at all, so that the remaining major part of the circuit opening movement of bridging contact 36 occurs extremely rapidly due to expansion of spring 86. Flange 89 is provided on rod 44 to obtain a positive contact separation in the event there is any sticking or welding of the bridging contact to stationary contacts 25, by engagement therewith of a shouldered sleeve 33 mounted in the upper end of actuating sleeve 32. In either case, it is apparent that toggle levers 52 and 54 will be moved to their on-center position in the manner previously described, and bridging contact 36 will be moved by spring 86 to its full open circuit position.

When the breaker contacts have attained their full open circuit position, the parts associated therewith are biased to return by gravity. This closing bias is relatively light and will be opposed by the dashpot action of core 76. Accordingly, the return movement will be relatively slow until pivot point 5% moves below the line of action of toggle spring 63 when toggle levers 52 and 54 are in engagement, whereupon bridging contact 36 will be rapidly moved to eflect a snap-action closing of the breaker contacts by toggle spring 68. it will be observed that during circuit closing movement of dashpot core 76, the dashpot action is due to the necessity of supplying liquid to the upper end of the dashpot through the relatively small clearance between core 7s and sleeves 74 and 82.

In order to provide for maintaining the breaker contacts separated and to also provide for manual operation, spring means are provided for holding the breaker contacts open in response to the occurrence of a prede- 'termined number of closely succeeding circuit interrupting operations, which means can be manually actuated. This means comprises a toggle lever 104 having a slot 106 at one end thereof for receiving a pin 108 mounted between spaced supporting arms 110 integral with cover casting 6. The other end of toggle lever 104 is pivoted, as by a pivot pin 112, to the adjacent end of a second toggle lever 114, and this, in turn, is mounted on a pivot pin 116 intermediate its ends on cover casting 6. A slot 120 is provided through the cover casting 6 for receiving the other end of toggle lever 114 which acts as a manual operating handle at the exterior of the circuit breaker casing, being provided with a hook eye 122 in its outer end. A coil compression spring 124 is mounted on toggle lever 104 and reacts between washers mounted on the toggle lever, one of which engages supporting pin 108, and the other of which engages a shoulder located adjacent pivot 112. Normally, toggle levers 104 and 114 are held with pivot 112 below the center-line connecting pins 1% and 116, with the outer end of lever 114 positioned in and beneath an integral hood 126 on cover casting 6, in engagement with an adjustable stop screw 128 mounted in the hood.

In the position of toggle levers 164 and 114 illustrated, they have no effect on operation of the circuit breaker as previously described, being normally inactive in this respect. However, the common pivot pin 112 of toggle levers 104 and 114 is extended at one side toward toggle levers 52 and 54 and in the normal position of the parts extends beneath the adjacent flange 56 of toggle lever 54. Accordingly, if it is desired to manually open the circuit breaker contacts, a hook stick or similar operating member may be inserted in hook eye 122 of toggle lever 114 and pulled downwardly to rotate the toggle lever in a counterclockwise direction about its supporting pivot 116 to move toggle levers 104 and 114 overcenter in an upward direction, and in doing this, the common pivot pin 112 engages the adjacent flange 56 of toggle lever 54 and moves it upwardly in a counterclockwise direction, thus carrying contact actuating rod 44 with it to separate bridging contact 36 from stationary contacts 26. The contacts will be held open by spring 124 which maintains toggle levers 104 and 114 in their upper overcenter position. With the breaker contacts maintained at their open circuit position following the manual circuit opening operation described above, it will be apparent that the outer end of toggle lever 114 projects below hood 126 of cover casting 6 so as to provide a readily visible indication that the breaker contacts are maintained at an open circuit position. It will further be apparent that the breaker contacts may then be closed only by manual operation of toggle lever 114 in the opposite direction, that is, by exerting an upward force on the outer end of the toggle lever to rotate it in a clockwise direction to move it and toggle lever 104 back overcenter to the position illustrated on the drawing. This manual operation of toggle lever 114 does not directly close the breaker contacts but merely permitsclosure of the contacts in the manner previously described, that is, initial closing movement of the contacts being due to the bias of gravity, until bridging contact 36 is closely adjacent stationary contacts 26 when toggle spring 68 is moved below its on-center position and suddenly becomes effective to finally move the contacts into engagement rapidly.

The structure thus far described is substantially identical with that of the patent applications hereinbefore referred to.

An integrating mechanism for automatically moving toggle levers 1&4 and 114 upwardly overcenter and thus preventing reclosure of the circuit breaker only in response to a predetermined number of closely successive circuit interrupting operations, and at the same time for automatically controlling the circuit opening and closing times in a predetermined manner in any sequence of a plurality of closely successive circuit opening operations, is provided comprising a cylindrical tube 130 secured in casting Zti, which tube is closed at the lower end. An integrating piston 136 is mounted in cylindrical tube 13% and normally rests on a shoulder 132 adjacent the lower end of the tube. The upper end of piston 136 is provided with a reduced extension 138 at the upper end thereof, having a plurality of spaced circular flanges 140 and having an elongated extension 142 on the extreme outer end thereof which is positioned below an extension 143 on toggle lever 104. A conduit 133 connects the lower end of the cylinder 130 to the passage 78 for supplying thereto, while the core 76 is operating to open the breaker, more than suflicient fluid to actuate the piston 136 upwardly the distance between flanges 40, each time the core 76 is actuated by the coil 24. A lever 144 is pivotally mounted at one end 'as by a pivot 146, with pivot l i-'6 supported on spaced supporting flanges 141 integral with casting 20. Lever 144 has a connecting web intermediate its ends, and at the other end thereof the sides of the lever are extended outwardly and laterally as at 145, to normally be in engagement with a washer mounted on sleeve 83 in engagement with an exterior shoulder on this sleeve. Lever 144 is normally biased into engagement with washer 150 by a coil tension spring 152 hooked over the remote edge of the web of the lever at one end and anchored to an ear integral With'casting it) at its other end. Lever 144 is provided with a stop member 154 thereon disposed to be actuated by the lever in a counterclockwise direction to a position wherein -a portion of stop member 154 is positioned above one or another of the flanges 14%) on the extension 138 so that it interferes therewith to limit upward movement of the piston 136 each time the core 76 is actuated. This provides for accurate stepping of the piston, regardless of the rate of movement of core 76.

In. order to control the opening and closing times of the circuit breaker contacts to provide for different open ing and closing times on predetermined circuit opening and closing operations in any sequence of closely successive operations, as on continuing overloads, the dashpot formed by sleeve 74 and solenoid core 76 is arranged so that fluid may escape from the upper end of sleeve 74 through annular vent 77 and passage 78, and then through a pair of opposed openings 1'77 and 178 in tube 130, from whence it may escape through a discharge opening 180, also formed in casting 20. Tl e openings 177 and 178 in integrator tube are aligned with passage 78 and discharge opening 180, and the piston 136 is disposed to control the passage through openings 177 and 180 as will be hereinafter described.

With the parts of the circuit breaker at their normal positions as illustrated, it will be apparent that when the circuit breaker operates to open the circuit, the upper end of dashpot sleeve 74 being open through annular vent 7, passage 78, openings 177 and 178 and discharge opening 18%, solenoid core 76 will be moved upwardly rapidly but not entirely free of restraint, since the liquid in dashpot sleeve '74 above the core is vented through the vent passages mentioned above, against the opposition produced by the reduced size of passages 77 and 78, and openings 177 and 178, relative to the area of the core 76, so that the initial circuit opening operation of the breaker will not occur instantaneously, but will be somewhat delayed.

As the solenoid core 76 moves upwardly on such a first circuit opening operation, washer 150 will be carried upwardly with actuating sleeve 82 and thus carry the free end of lever 14 upwardly with it to move stop member 154 to a position above the upper one of flanges on integrating piston 136. At the same time core 76 pushes t e liquid out of the dashpot through passage 78. A sutllcient pressure is developed in this passage to force more than sufficient liquid through conduit 133 into cylinder even on relatively light overloads, to raise the piston until the upper flange 1 5-9 interferes with and engages stop 15d, and thus carry the piston upwardly a predetermined distance throughout opening movement of sleeve 82. Integrating piston 1st; is therefore, carried upwardly a distance not suificient to entirely remove reduced portion 138 thereof from between openings 177 and 17% in cylinder 130, so that the vent passageway from the upper end of dashpot cylinder 74 will still not be blocked off by piston 136. When the breaker recloses following such a first fast circuit interrupting operation, such reclosure will also occur extremely rapidly because core 76 does not have much action in its dashpot sleeve 74* due to the vent for the sleeve still being open. Accordingly, the first opening and reclosing of the circuit breaker contacts will both occur relatively fast, with but little time delay interposed, due to the dashpot action of core id in dashpot sleeve 74.

uuring since stop member 15 is free to disengage the circular flanges and is returned to the position shown by spring 152, and if the breaker remains closed, integrator piston 136 will slowly reset to the position shown in the drawing, this resetting movement being relatively slow due to the necessity of displacing liquid drawn into the lower end of cylinder 13% by displacement of piston 136 during the opening operation, past the relatively small clearance between cylinder 13% and piston 136. This means, of course, that if an overload appears on the circuit at a later time, the oreaker contacts will then be opened and closed with only the initial amount of time delay in the manner described above.

if the breaker immediately reopens after a first opening and reclosing operation, more liquid will be pumped by the core 76 into the passage 7 and through the conduit 133 for further raising the piston 136. The stop member 154 this time will be actuated so as to be positioned above the next lower circular flange 140 on the integrator cylinder 130 as the piston is forced up by fluid pressure, so that the integrator piston 136 acts as a valve to close off the vent passage 78 from the upper end of dashpot cylinder 74. Inasmuch as the integrator piston 136 does not close the vent passage until bridging contact 36 is substantially at the end of its circuit opening movement, this second closely successive circuit opening operation will, like the first, occur relatively quickly, with only a slightly increased delay due to dashpot action of cylinder 74 and core 76. On the succeeding reclosing operation, integrator piston 136 having closed the vent at the top of dashpot cylinder 74, this reclosing operation will be materially delayed throughout in the manner previously described by the dashpot action of core 76 in cylinder 74. This second reclosing operation will result in leaving piston 136 at the further advanced position described above, from which it eventually will reset in the manner previously described, if the breaker remains closed, so that an overload appearing on the circuit at a later time Will result in the breaker operating in the manner described above for the first and second closely succeeding circuit opening and closing operation. However, in the event the overload continues after the second closely succeeding circuit opening and closing operations, the breaker will again open, and this time the opening operation will be delayed by the full dashpot action of core 76 in dashpot sleeve 74, since integrator piston 136 has not had time to recede from the position to which it was advanced on the second opening operation of this series of closely succeeding circuit opening operations, where it substantially blocks the vent passage from the upper end of dashpot sleeve 74.

The circuit closing operation of the breaker following the third opening will also be delayed by the full dashpot action in the manner previously described, inasmuch as such third opening operation results in further advance of integrator piston 136 where it still blocks opening 177 of the vent passageway from the upper end of dashpot sleeve 74. The breaker may then continue to open and reclose if the overload continues, with each opening and closing being delayed by the dashpot action of core 76 in dashpot sleeve 74 until finally the pumping action of core 76 in conjunction with the stop action of stop 154 results in the integrator piston 136 being advanced an amount sufficient to cause the upper extension 142 thereof to engage extension 143 of toggle lever 10 i, and move this lever upwardly overcenter so that toggle spring 124 will maintain the contacts separated in the manner previously described. It is thus apparent that toggle levers 104 and 114 will be automatically moved upwardly o-vercenter to maintain the breaker contacts separated, only in response to a predetermined number of closely successive circuit opening and closing operations, usually four such operations; however, in the event a lesser number of closely successive opening and closing operations occurs, the integrating mechanism will reset and the breaker contacts will be automatically held open only when the aforesaid predetermined number of opening and closing operation occurs in close succession. Obviously, after the breaker contacts have been automatically actuated to a position where they are held open by toggle spring 124, they can be reclosed only by manual operation of toggle lever 114 in themanner previously described.

In the preferred sequence of operations leading to the breaker contacts being maintained in open circuit position mentioned above, that is, a sequence of four operations, it will be apparent that with the apparatus described above, the first two opening operations will occur substantially instantaneously and the second two opening operations will be delayed with an inverse time-current characteristic due to the dashpot action of core 76 in dashpot sleeve 74. Moreover, the reclosing times in any such sequence of four closely successive opening and closing operations will comprise a first relatively fast closing operation, with but a momentary delay,

with the remaining circuit closing operations being delayed the full amount throughout, by the dashpot action of core 76 in dashpot sleeve 74.

It is believed apparent that this invention provides a simple and accurate method of counting closely successive operations of an automatic reclosing circuit breaker. By providing more than the necessary liquid under pressure from the time delay dashpot for operating the cour ing piston and limiting motion of the counting piston to a definite amount by means of a mechanical stop, accurate stepping of the piston is obtained, regardless of whether the core moves slowly or rapidly, depending on whether the overload is slight or heavy. .Ny invention requires a minimum of parts, and is simple and in expensive to maintain.

Having described a preferred embodiment of the in vention in accordance with the patent statutes, it is de sired that this invention be not limited to this particular structure inasmuch as it will be apparent, particularly to persons skilled in the art, that many modifications and changes may be made in this particular structure without departing from the broad spirit of the invention. Accordingly, it is desired that the invention be interpreted as broadly as'possible and that it be limited only as required by the prior art.

I claim as my invention:

1. An automatic reclosing circuit breaker comprising, separable contacts, electroresponsive means having a part movable in response to an overload current to effect separation of said contacts, counting means, locking means activated by the counting 'means after a predetermined advance to eifect locking of said contacts in the separated position, means actuated by said part to apply an operating force to advance the counting means sufiicient to more than efifect a counting operation, and means actuated by said electroresponsive means to en gage and determine successive operating positions of said counting means substantially independently of the value of the overload current.

2. An automatic reclosing circuit breaker comprising, separable contacts, electroresponsive means having a part movable in response to an overload current to effect separation of said contacts, counting means, locking means actuated by a predetermined number of operations of the counting means to lock said contacts in a separated position, fluid pressure means applying fluid pressure to operate the counting means in response to movement of said part of the electroresponsive means, and means actuated by movement of said movable part of said electroresponsive means to engage and determine the position of the counting means.

3. In an automatic reclosing circuit breaker, separable contacts, electroresponsive means having a part operable in response to an overload current to effect separation of said contacts, said contacts being biased to reclose upon separation, movable counting means, locking means actuated by the counting means to lock said contacts in an open position after a predetermined number-of operations, fluid pressure means applying fluid pressure to said counting means to advance it in response to operation of said part of the electroresponsive means, and means actuated by movement of said part of the electroresponsive means operable to successively engage and stop the counting means in different predetermined positions on closely succeeding operations substantially in dependently of the value of the overload current.

i 4. An automatic reclosing circuit breaker comprising, separable contacts, electroresponsive means having a part movable to effect separation of the contacts in response to a fault current, said contacts being biased to reclose after separation, counting means, locking means actuated by the counting means to lock the contacts in a separated position after a number of stepping operations, fluid pressure means actuated .by'rnovement of said movable part applying a force to the counting means,

9 and movable stop means actuated by movement of said part of the electroresponsive means to engage and stop the counting means in different predetermined positions on different ones of closely successive operations.

5. An automatic reclosing circuit breaker comprising, separable contacts, electroresponsive means having a part movable in response to an overload current to effect separation of the contacts, means biasing said contacts together, fluid pressure delay means acting on said movable part operable to delay separation of said contacts, counting means operable after a predetermined number of operations to lock the contacts in a separated position, fluid pressure means operated by said part actuating the counting means at least a predetermined amount each time the delay means operates, and stop means actuated by movement of said movable part of the electroresponsive means interposed in the path of movement of the counting means to limit motion of the counting means to no more than a definite amount each time the contacts separate. 1

6. In an automatic reclosing circuit breaker, separable contact means, electroresponsive means having a movable part operable to effect separation of the contact means, means biasing the contact means to close them after separation, fluid dashpot means acting on said part operable to delay operation of said electroresponsive means said dashpot means having a vent, counting means advanceable to different positions and having a valve portion blocking said vent to control venting of the dashpot means and change the operating time of the electroresponsive means, conduit means connecting the dashpot means and counting means supplying fluid from the dashpot means for operating the counting means, and stop means actuated by movement of said movable part of the electroresponsive means to interfere with movement of the counting means and prevent more than a predetermined change in the operating position of the counting means each time the contacts separate.

7. An automatic reclosing circuit breaker comprising, separable contacts, electroresponsive means having a movable part responsive to an overload current to cause separation of said contacts, time delay means acting on said part delaying separation of said contacts, said contacts being biased to reclose following separation, counting means having a movable part linked to said electroresponsive means to be actuated to successively advanced positions by closely successive operations of the electroresponsive means to vary the effectiveness of the delay means, stop means operated by movement or" said part of the electroresponsive means to block advance of the counting means and determine the operating position of the counting means, and means actuated by operation of the movable part of the counting means to a predetermined operating position to lock the contacts in a separated position and prevent further reclosing thereof.

8. In an automatic reclosing circuit breaker, separable contacts, electroresponsive means having a moving part operable to effect separation of said contacts, fluid dashpot means acting on said part to delay operation of the electroresponsive means, said dashpot means having a vent, valve means controlling said vent to vary the delay of the electroresponsive means, conduit means supplying pressure fiuid from the dashpot means to actuat: aid valve means, and stop means actuated by movement of said moving part of said electroresponsive means to engage and accurately stop said valve means in different predetermined positions on closely successive separations of said contacts.

9. An automatic reclosing circuit breaker comprising, separable contacts, a solenoid coil responsive to an overload current to move a magnetic core, means actuated by said core to cause separation of said contacts, time delay means acting on said core operable to retard movement of said core, counting means advanceable to different positions to vary the effectiveness of the time delay means and control the retardation of the core, fluid pressure means operated by movement of the core to advance the counting means in response to energization of said solenoid coil by an overload, and means actuated by the core to interfere with movement of the counting means and determine the operating position of said counting means.

10; An automatic reclosing circuit breaker comprising, separable contacts, electroresponsive means having a movable part operable in response to an overload current to efiect separation of said contacts, means biasing said contacts to reclose them after a separation, fluid pressure dashpot means acting on said part to delay separation of said contacts, said dashpotmeans "having a vent, valve means operable to vary the effective size of said vent and change the delay in separation of said contac m ans including a conduit connecting said vent to a chamber to supply fluid from the dashpot to operate the valve means, and a movable stop operated by movement of the moving part'of the electroresponsive means to interfere with and limit movement of the valve means to a definite amount each time the contacts separate.

11. in an automatic reclosing circuit breaker, separable contacts, electroresponsive means having a movable part operable in response to an overload current to effect separation of said contacts, biasing means effecting engagement of said contact-s upon separation, fluid dashpot means acting on said part operable to delay separation of said contacts, said dashpot means having a vent, a cylinder having a movable piston disposed to control said vent, conduit means connecting said cylinder and dashpot means to supply fluid under pressure to said. cylinder from said dashpot means to actuate the piston, and stop means actuated by the movable part of said electroresponsive means for engaging and limiting movement of said piston to a definite amount each time the contacts separate.

12. An automatic reclosing circuit breaker comprising, separable contacts, electroresponsive means having a movable part operable in response to an overload current to effect separation of said contacts, biasing mei ns effecting engagement of said contacts upon separation, fluid pressure dashpot means acting on said part delaying separation and engagement of said contacts, a cylinder having a movable piston controlling venting said dashpot means, conduit means supplying pressure fluid from the dashpot means to said cylinder to ad vance the piston to different positions, stop means actuated by movement of said part in response to operatin of the electroresponsive means to limit such movement of the piston to a predetermined amount each time the contacts separate, and means actuated by a predeterm ned number of closely successive advances of the piston to effect separation of the contacts and lock them in a separated position.

13. An automatic reclosing circuit breaker comprising, separable contacts, electroresponsive means havi g a part movable in response to an overload current to effect separation of said contacts, biasing means reclosing said contacts when they separate, dashpot means acting on said part and delaying separation and reclosing of said contacts, said dashpot means having a vent, a cylinder having a movable piston controlling said vent, said piston having an extension with a plurality of spaced flanges, conduit means connecting the cylinder to the dashpot means to supply more than suflicient the clyinder to move the piston a distance equal to space between flanges each time the contacts separa e, and a lever having a stop portion thereon, said lever being actuated by movement of said part or" t, e electroresponsive means to position said stop portion in interfering relation with one of said flanges each time the contacts separate, so as to limit the movement of the piston,.

14. An automatic reclosing circuit breaker comprising, separable contacts, electroresponsive-means having a part operable in response to an overload current to eflect separation of said contacts, means reclosing said contacts following separation, fluid dashpot means acting on said part delaying separation of said contacts, means including fluid actuated counting means having a fluid connection with the dashpot means supplying thereto on each operation of the electroresponsive means fluid from said dashpot means to effect successive advance movement of the counting means to lock the contacts in a separated position after a predetermined number of operations, and stop means operated by said part to engage the counting means and permit only a predetermined movement of said counting means each time the contacts separate.

15. In an automatic reclosing circuit breaker, separable contacts, electroresponsive means having a movable part operable in response to an overload current through said contacts -to effect separation thereof, time delay fluid dashpot means operating on said part to delay separation of said contacts, counting means having a fluid connection with the dashpot means supplying additional fluid to the counting means on each of closely successive operations to advance the counting means, stop means actuated by the electroresponsive means for engaging and limiting the movement of the counting means to a predetermined amount each time the contacts separate, and means responsive to a predetermined number of operations of the counting means for preventing reclcsing of said contacts.

by J. M. Wallace, 10 pp. (p. 8, Fig. 2). 

